The eight levels of Penguin Readers follow the Common European Framework of Reference for language learning (CEFR). Exercises at the back of each Reader help language learners to practise grammar, vocabulary, and key exam skills. Before, during and after-reading questions test readers' story comprehension and develop vocabulary.

The Railway Children, a Level 1 Reader, is A1 in the CEFR framework. Short sentences contain a maximum of two clauses, introducing the past simple tense and some simple modals, adverbs and gerunds. Illustrations support the text throughout, and many titles at this level are graphic novels.

Bobbie, Peter, Phyllis and their mother have to leave London and live in the countryside. Their new house is next to the railway, and the children visit it every day. Slowly, the children begin to love their new life.